In the field of aeronautics, there are different types of known wing structures, especially wing structures provided with two wings positioned on either side of a fuselage of the aircraft. For example, there is a known wing structure provided with two upper wings, i.e. the wings are laid on the fuselage in such a way that, seen in profile, each wing in its entirety is placed above the fuselage. There is also a known wing structure provided with two median wings. The median wings are fixed in the neighborhood of the diametric plane of the fuselage. Finally, there is a known wing structure with lower wings. In this case, the intrados or lower surface of the wing goes through the fuselage.
Furthermore, there are known aircraft provided with a ventral fairing. For example, in the case of a wing structure with low wings, the ventral fairing is fixed to the position of a lower part of the fuselage, at the intersection of the fuselage with the wing structure. The ventral fairing blocks the lower part of the fuselage. The cradle-shaped ventral fairing is provided with a base and two flanges or longitudinal panels rising up laterally on either side of said fuselage. Each panel is provided with an opening capable of letting through a wing of the wing structure of the aircraft.
In certain cases, there is a known way of positioning a seal on an inner rim of each opening, namely between an internal wall bordering the opening and the wing crossing said opening. Such a seal must prohibit the circulation of air inside the fairing through the opening. Indeed, an air passage of this kind prompts a vibration of the seal. This vibration may create a noise that is audible inside the cabin of the aircraft, thus creating auditory discomfort for occupants of the cabin. Furthermore, this vibration is transmitted to the fuselage and to the elements that it comprises, giving rise to structural stress and fatigue in those elements. Furthermore, the vibration of the seal favors a wearing out of the seal and the wearing out may lead to a premature tearing of the seal. Finally, this vibration gives rise to parasitic aerodynamic drag.
In certain aircraft, the seal in the upper surface region of the wing travels from the structure fastening the wing to the fuselage up to the upper surface and/or lower surface of the wing. Now, generally, the fastening structure forms an extra thickness at the position of the upper surface and/or lower surface of the wing. For example, the fastening structure is a linking metal fitting used to hold the wing to the fuselage. A first part of the metal fitting is fixedly joined to the fuselage while a second part of the metal fitting is fixedly joined to the upper surface of the wing. The second part of the metal fitting is fixed by any means to the upper surface of the wing. A thickness of the second part of the metal fitting, fixedly joined to the upper surface of the wing, thus forms an extra thickness on the upper surface of the wing that may go up to about 15 millimeters. Thus, the seal, traveling from the fastening structure to the upper surface of the wing, is subjected to a difference of level. A difference of level of this kind may lead to poor adhesion of the seal at the position of a zone of transition between the fastening structure and the upper surface of the wing, i.e. the seal will not be sufficiently compressed between the wall bordering the opening and the transition zone between the fastening structure and the upper surface of the wing. This results in a passage of air from the exterior to the interior of the ventral fairing.